WILLIAMSAvailable on-line ET AL.:at: http://www.newzealandecology.org/nzje/ PHYSIOGNOMIC FRAMEWORK FOR RARE ECOSYSTEMS 119

REVIEW New Zealand’s historically rare terrestrial ecosystems set in a physical and physiognomic framework

Peter A. Williams1*, Susan Wiser2, Bev Clarkson3 and Margaret C. Stanley4 1Landcare Research, Private Bag 6, Nelson 7010, New Zealand 2Landcare Research, PO Box 40, Lincoln 7640, New Zealand 3Landcare Research, Private Bag 3127, Waikato Mail Centre, Hamilton 3240, New Zealand 4Landcare Research, Private Bag 92170, Auckland Mail Centre, Auckland 1142 *Author for correspondence (Email: [email protected])

Published on-line: 3 December 2007

______Abstract: Terrestrial ecosystems that were rare before human colonisation of New Zealand often have highly specialised and diverse flora and fauna characterised by endemic and nationally rare species. Although many of these ecosystems are under threat from anthropogenic modification and their biodiversity values are declining, they still are not adequately identified by current land classifications. We compiled a list of 72 rare ecosystems from the literature and by canvassing New Zealand ecologists and land managers. Rare ecosystems are defined as those having a total extent less than 0.5% (i.e. < 134 000 ha) of New Zealand’s total area (268 680 km2), and the resultant list includes both well-recognised and less well known ecosystems. To define the ecosystems in a robust fashion we developed a framework based on descriptors of physical environments that distinguish rare ecosystems from each other and from more common ecosystems. Using this framework the 72 rare ecosystems are defined using pertinent environmental descriptors selected from soil age, parent material, soil chemistry and particle size, landform, drainage regime, disturbance, and climate. For each ecosystem, an example locality and ______the dominant vegetation structural type are also given. Keywords: ecological classification; New Zealand; rarity; threatened terrestrial ecosystems

Introduction Many of these ecosystems were historically rare, i.e. rare prior to human colonisation of New Zealand. They New Zealand’s complex topography and climate have do not include ecosystems in common environments that created a diverse array of terrestrial ecosystems. Many are now rare because of stochastic events, however; for of these are small, widely dispersed, and often lack example, distinct tree species combinations on isolated trees due to extreme environments. These distinctive mountain tops, or ecosystems largely destroyed during ecosystems may exhibit corresponding extremes of the human period, such as kahikatea (Dacrycarpus biotic diversity (i.e. have diverse flora or fauna or dacrydioides) forest on alluvium. ‘Rare’ encompasses ecosystems that are small in be particularly depauperate), may have high national 2 endemism (e.g. Carex ophiolithica and Coprosma size (e.g. 100 m to a few hundreds of hectares) but spathulata subsp. hikuruana and other endemics geographically widespread (e.g. dune deflation hollows on ultrabasic cliffs in Northland), and may support along the New Zealand coast), to those that are larger (e.g. specialised life forms (e.g. halophytes in salt pans, ten thousands of hectares) but geographically restricted tropical taxa in geothermal areas). Furthermore, these (e.g. frost flats on the volcanic plateau) (cf. Rabinowitz ecosystems often provide important refuges for native 1981). We limit the total extent of any individual type of historically rare ecosystem to less than 0.5% (i.e. < plant and animal species within highly modified 2 landscapes (e.g. braided riverbeds – Williams & 134 000 ha) of New Zealand’s total area (268 680 km ). Wiser 2004; frost flats – Smale 1990; saline patches Our geographic scope includes the main islands of New – Rogers et al. 2000; tors, cliffs and scarps – Rogers Zealand – North, South and Stewart. (More remote islands & Walker 2002). such as the Kermadec Islands, subantarctic islands, and the Chatham Islands are excluded.)

New Zealand Journal of Ecology (2007) 31(2): 119-128 ©New Zealand Ecological Society 120 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 31, NO. 2, 2007

We use the definition of an ecosystem suggested (e.g. sand dunes). These classifications based on abiotic in Henderson & Henderson (1963) as an ‘ecological criteria were not designed to identify historically rare system formed by the interaction of co-acting organisms environments, however. First, the current resolution (for and their environment’. An ecosystem type is therefore LCDB2 and LENZ the minimum mapping units are 1 ha one type of ecological system that can be differentiated and 25 m, respectively) cannot detect environments such from another ecological system by one or more abiotic as ephemeral wetlands bordering karst lakes, which are or biotic factors. Groups of organisms that co-occur patches only metres across. Second, there are aspects within the ecosystem and interact through trophic or of the environment that are not represented by LENZ spatial relationships are considered to be communities (e.g. geothermal environments). Third, planar maps of (Lincoln et al. 1982). The microhabitats of individual surface projections cannot depict subterranean systems organisms, such as logs on a forest floor, are at too fine and vertical surfaces, such as cliffs. Last, tools such as a scale to be classed as ecosystems for our purposes. LENZ do not utilise biotic drivers (e.g. the effects of Collectively, historically rare ecosystems marine mammals) to identify rare environments such contain half of New Zealand’s nationally threatened as those associated with seal colonies. Consequently, plant species (PA Williams unpubl., based on data a system that is complementary to LENZ is required of de Lange et al. 2004). Similarly, 38% of the 160 to define and name physical environments of nationally threatened Lepidoptera live in ecosystems terrestrial ecosystems that were historically rare in that are themselves limited in distribution nationally New Zealand. (e.g. Dugdale 2001). This rarity at different trophic levels increases both the intrinsic interest and the Vegetation importance of rare ecosystems as foci for attention The Atkinson (1985) system for naming and delineating in biodiversity conservation initiatives (e.g. DOC & vegetation types is widely used in New Zealand MfE 2000, 2007). and is applicable to all terrestrial ecosystems. It Historical and recent losses of indigenous cover comprises two components, species composition and have been well documented by Walker et al. (2006), vegetation structure (or substrate where vegetation but data pertaining to loss of individual rare ecosystems is sparse or absent), and can be applied at a range of are lacking. Historically rare ecosystems face many scales. Vegetation has often been used as a surrogate threats, e.g. housing development (coastal sand dunes), measure for biota in natural ecosystems as vegetation weed invasions (braided riverbeds), and agricultural is immobile, easy to measure, and provides habitat for development (salt pan vegetation). Greater community most other biota (Myers et al. 1987). and agency awareness of historically rare ecosystems and their importance will hopefully lead to greater Ecosystem protection and appropriate management that will arrest their decline. Two of the better known New Zealand classification To these ends we provide an initial list of historically systems concern only forests (McKelvey 1984) and rare ecosystems and a consistent framework for wetlands (Johnson & Gerbeaux 2004). However, a delineating and mapping them. system developed to apply to the full array of ecosystem types evolved during the Protected Natural Areas Programme (PNAP) (Kelly & Park 1986; Myers et al. 1987). This classification was designed to identify Existing classifications representative examples of the full range of natural Existing classifications can be grouped broadly ecosystems within each ecological district, with the into those based on abiotic criteria, vegetation, or ultimate goal of enhancing biodiversity conservation ecosystems. (McEwen 1987). It is a hierarchical system and uses expert knowledge to subdivide each ecological district Abiotic into ecological classes (defined by bioclimatic zone, hydrologic class, and land system and vegetation Existing national environmental and land-cover structure). Ecological classes are further subdivided into classifications (e.g. Land Environments of New Zealand ecological units, which describe specifics of landforms, (LENZ; Leathwick et al. 2003) and the Land Cover and vegetation (Atkinson 1985) types. The PNAP Database (LCDB; Thompson et al. 2004) are applicable approach has provided some intuitively sound regional to common and dominant environments and vegetation. classifications (e.g. Courtney & Arand 1994), but no Nevertheless, some environments that we consider rare synthetic work has been done to enable classifications have been identified and mapped by these classifications. to be scaled up from a regional to national scale and For example, LCDB2 identifies braided riverbeds and hence to be applicable to rare ecosystems nationally. screes, and LENZ identifies ultrabasics and other areas within which rare or uncommon environments occur WILLIAMS ET AL.: PHYSIOGNOMIC FRAMEWORK FOR RARE ECOSYSTEMS 121

A framework for defining Our framework differentiates the physical environments of rare ecosystems from more common the physical environments of ecosystems and from each other by aggregating diagnostic classifiers (sensu Corner et al. 2003) of historically rare ecosystems abiotic and biotic environmental factors into unique combinations (e.g. coastal sites, occurring on sand, We use a modular or multi-factor (sensu Corner et al. having a depression landform and being excessively 2003) approach using physical and biotic factors to define well drained). Comparable modular systems have been and name the physical environments of historically rare used to classify North American terrestrial systems ecosystem types. This approach provides maximum (Corner et al. 2003). The choice of environmental flexibility to define these environments and make factors and classifiers is critical to the success of the changes or additions. The framework builds on the framework. First, they must enable the description and environmental drivers underpinning LENZ, the first differentiation of treeless ecosystem types occurring level of the hierarchical approach used in the PNAP below the treeline, e.g. on cliffs, sand dunes, and surveys (Myers et al. 1987), the biophysical component ephemeral wetlands. Second, they must enable the of Lawless et al. (1994, unpubl. draft report to the description of environments supporting ecosystem types Department of Conservation), and the first level of that are rare in the alpine zone but not restricted to it the wetland classification, which is based primarily (e.g. ultrabasic hills), as well as those that are restricted on hydrological and landform setting, salinity, and to the alpine environment (e.g. snow banks). Third, they temperature (Johnson & Gerbeaux 2004). must enable any rare forested ecosystem types occurring Our framework specifically pertains to terrestrial in extreme environments to be distinguished. ecosystems. We include only those wetland types (sensu The following seven factors used in Tables 1 and Johnson & Gerbeaux 2004) dominated by terrestrial 2, (1) soil age, (2) the nature of the parent material or plants, or emergent hydrophytes as opposed to aquatic the chemical environment of the soil, (3) the size of hydrophytes (Tiner 1991). Thus, we exclude permanent the particles making up the soil, (4) the landform on freshwater bodies such as ponds, lakes and lagoons, which the soil and its associated ecosystem is found, and the aquatic component of water channels and (5) the drainage regime of the landform, (6) any major springs below the depth limit of rooted plants (littoral disturbances influencing the system, and (7) the climate zone) such as the aquatic communities of braided regime, are described in that order, based on their rivers. Estuaries below mean minimum low water and perceived power to discriminate systems. We do not marine systems below mean maximum high water are presume, however, that a definitive hierarchy exists. also excluded. For example, for ultrabasic or geothermal ecosystems, the parent material or chemical environment may be the The drivers: factors that distinguish and differentiate primary aspect of their environment that distinguishes environments them from more common ecosystems, whereas sand Soil types and their profiles provide an indication of dunes are formed from a wide range of parent rock types factors influencing landscapes. Work by Hans Jenny but their particle size and landform are their principal (1941) described soil as the product both of biotic factors distinguishing features. (plants and animals) and abiotic factors: climate (at a regional scale), parent material, topography (landform Soil age and drainage), and time since soil formation began. The effective time since soil formation began has a These ideas underpin the ecosystem concept used here, major influence on organic matter accumulation and whereby the biotic factors become a function of abiotic nutrient supply capacity of the soil. Plants are capable factors. Rare ecosystems are often found in climatically of growing on substrates with no organic matter, here or topographically extreme environments that may termed raw soils (Hewitt 1992), e.g. fresh sand forming prevent or delay vegetation succession. For example, dunes under marram grass (Ammophila arenaria). If the chemistry of the soil parent material prevents an the substrate and vegetation are not disturbed, organic ultrabasic site below the treeline from developing into matter will accumulate in the upper part of the soil forest, whereas insufficient time for soil formation, column, as indicated by dark staining, to form recent because of parent material instability, prevents active soils (Hewitt 1992), e.g. old sand dunes under scrub. sand dunes from supporting forest. In some situations, the Over time, in the order of thousands of years, and factors may result in an induced vegetation type (sensu depending on the other soil-forming factors, a wide Kelly 1972) that may dominate for hundreds of years range of soils showing recognisable horizons may (e.g. frost flat heaths). However, shorter term successions develop, e.g. yellow-brown earths (Taylor & Pohlen on typical soils such as those on regularly eroding hill 1962). For convenience, these are termed mature soils. In slopes are excluded from our classification. the lowlands, these mostly supported forest in prehuman 122 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 31, NO. 2, 2007

times. Eventually, however, if there are no inputs of Topography: landform and drainage fresh material into the soil column from the bedrock or Topography has two components sensu Taylor & Pohlen other sources such as river alluvium, the soil may pass (1962): landform (e.g. cliff), which determines the its peak of pedogenesis. The physical, chemical and relief (e.g. slope), and drainage, which is the rate and biological properties of the soil–vegetation system will degree of the removal of water. They have a multitude become so rundown (often in association with drainage- of effects ranging from preventing plant growth through impeding subsurface pans of one sort or another) that instability and non-development of the soil substrate the soil can no longer support tall forest, e.g. the pakihi because of previous or ongoing steepness, to controlling soils of Westland. Such soils can be termed over-mature. the water-table level and soil drainage. We have adopted Because historically rare ecosystems occur mostly at the landform terminology of Speight (1990). Where the the extremes of environmental gradients, they mostly drainage effect results in a permanently to seasonally comprise raw, recent, or over-mature soils. high water table, or open water, and where plants and animals adapted to the wet conditions are present, the Parent material or chemical environment environment is classed as a wetland. For completeness, Soil parent material, whether derived directly from the subterranean systems (e.g. caves), which support a underlying rock or redeposited from elsewhere, is the unique and distinctive fauna, are included. primary determinant of soil fertility (i.e. its available P, cations, pH). The first diagnostic classifier describing Disturbance regime parent material indicates chemical composition Disturbance of varying degrees is a universal feature of of the parent rock (Table 1). Parent rock types are ecosystems. Ongoing disturbance is implied in several grouped into five broad classes according to chemistry of the diagnostic classifiers associated with the factors – quartzose, acidic, basic, ultrabasic, and calcareous described above (e.g. dune landforms). We use the – following Lilburne et al. (2004) and Barringer et term to describe only irregular disturbance that is not al. (2006). Soil fertility tends to increase in the order implied in other diagnostic classifiers but is required to listed above (quartzose to calcareous), but alkaline maintain the ecosystem type. The diagnostic classifiers soils resulting from ultrabasic parent materials may of abiotic disturbance regimes include periodic flooding have concentrations of heavy metals that are toxic to and periodic fire. Braided riverbeds are maintained plants. To define the environments of historically rare by periodic flooding, and periodic natural fires are a ecosystem types, either the broad parent material class characteristic disturbance regime of some ecosystems (e.g. acidic rock) or the more specific rock type (e.g. such as the gumlands in Northland. granite, sandstone, and basalt) is used. Parent materials Native vertebrates may also generate disturbance may also include other substances such as loess, marine that creates rare ecosystems. For example, seabird shell beds, and peat (Table 1). activity may result in soil disturbance caused by Some ecosystem types are influenced by chemical burrowing and trampling and high nutrient status factors that are not derived directly from the soil parent through fertility imported in guano. Wetland turfs material but from groundwater (which may contain may develop in the presence of masses of waterfowl dissolved salts and heavy metals, for example), air (e.g. that trample, browse and fertilise. Seal activity can acid rain derived from geothermal activity, atmospheric also create localised vegetation communities. Animal salinity resulting from salt spray), or water movement activity would have been widespread in New Zealand (e.g. seepages and flushes carrying enhanced nutrients). before human arrival and, combined with unusual These diagnostic classifiers are incorporated within topography or geology, may have supported a variety parent material or chemical environment in Table 1. of rare environments.

Parent material particle size Climate The third diagnostic classifier describing parent material Climate is a key determinant of plant growth via indicates dominant particle size (also called ‘grain temperature, radiation, and precipitation. Coarse-scale size’). Particle size influences local terrain (e.g. sand is climatic conditions are depicted in existing New Zealand blown to create dunes) and soil properties, particularly climate and ecosystem classifications (e.g. Meurk 1984; moisture availability and nutrient-exchange sites. Myers et al. 1987; Wardle 1991). Climate is used in two Particle size follows the widely used Udden–Wentworth ways here. First, the climatic component of the above scale (Wentworth 1922; Table 1). More than one classifications is reduced to three coarse categories, parent-material diagnostic classifier may be used, e.g. ‘coastal’, ‘inland’ and ‘alpine’ to portray geographically calcareous/boulders. where the listed physical environments typically occur. These geographical categories do not distinguish rare environments from common ones, however, so we use WILLIAMS ET AL.: PHYSIOGNOMIC FRAMEWORK FOR RARE ECOSYSTEMS 123

climate only as a diagnostic classifier (Table 1) when to define the environment of a specific ecosystem type the physical environment of the rare ecosystem type where climate combines diverse drivers (e.g. high cloud is differentiated by a climatic factor that is extreme cover, a high number of frosts annually, extreme wind within the New Zealand context. Thus, climate may exposure). act on a regional scale, such as in the semi-arid zone of Central Otago where nationally unique ecosystem Using diagnostic classifiers to define and name types occur (e.g. salt pans occurring on inland saline physical environments soils). More typically, climate may differentiate rare Diagnostic classifiers from each or any of the seven ecosystem types at a local scale; for example >200 classes of physical and biotic factors listed above frost days per year resulting from cold-air ponding (soil age, parent material or chemical environment, differentiates frost flats from adjacent hillslope forests. particle size, landform, drainage, disturbance regime, Multiple diagnostic classifiers for climate are required and climate) can be combined to define the physical

Table 1. Diagnostic classifiers that when combined distinguish the physical environments of historically rare ecosystem types from each other and more common environments. They comprise six classes of physical factors (soil age, parent material chemistry, particle size, landform, drainage, climate) and one class describing disturbance. ______Soil age1 Parent Particle size (Udden– Landform2 Drainage Disturbance Climate material/chemical Wentworth scale) Regime ______environment

Raw Quartzose rocks Bedrock (in situ) Hillslope3 Excessive Abiotic Coarse-scale4 Recent Soft quartzitic Boulders >256 mm Hillcrest5 drainage Periodic fire Coastal Mature sediments Cobbles 64–256 mm Plain (including Inland Over- Quartzite Gravel 2–64 mm Terrace Near eruptions) Alpine mature Acidic rocks Sand 62.5 µm–2 mm Fan permanently Mudstone (soft) Silt and clay <62.5 µm Depression6 saturated (but Periodic Fine-scale Sandstone (soft *Gorge water table not flooding >200 frost days per Mudstone (hard) Doline high) year Sandstone (hard) – Tor Biotic greywacke Cliff Permanently Seabirds – High water balance Rhyolite Scarp high water guano deposits (high–very high Granite and gneiss Talus table monthly water Schist *Moraine Seabirds and balance ratio7 Basic rocks Beach ridge Regularly high marine Tuffaceous mudstone Beach water table mammals – High cloud cover Tuffaceous sandstone Dune (comprised trampling and (<1500 sunshine Andesite of dune crest and Seasonally grazing hours and >200 Diorite dune slope) high water rain days p.a.) Basalt *Cave entrance table Seabirds – Gabbro *Subterranean (e.g. (periodically burrowing Semi-arid (high– Ultrabasic rocks caves and cracks) dry) very high annual Calcareous rocks Estuary water deficit)7 Limestone Lagoon Open water Marble *Dome Extreme wind Other parent exposure substrates Alluvium and till Late snowlie Loess Shells Geothermal – Peat excessive heat Dune sand8 Geothermal – Chemical superheated steam environment Groundwater salinity Atmospheric salinity Geothermal – acid rain Geothermal – acid soils, toxic elements ______Enhanced nutrients 1 Following Hewitt (1992) and Leathwick et al. (2003) 2 A subset of those listed in Speight (1990). *= not listed in Speight 3 Includes mountain slopes 4 Coastal = coastal (within 1 km of the coast and with altitude <300 m); inland = lowland, montane, subalpine; alpine = lower alpine, upper alpine, nival – of Myers et al. (1987) 5 Includes ridges and summits 6 Includes hollows, basins and swales 7 Following Leathwick et al. (2003) 8 Derived from a combination of particle size and landform 124 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 31, NO. 2, 2007

environment of an individual ecosystem type (Table 2). the parent rock, whichever is applicable. For example, Diagnostic classifiers are listed only if they are perceived environments of ecosystem types on coastal sand are by the authors as being critical to distinguish ecosystem subdivided on the basis of soil development, whereas types from each other. For example, a ‘shingle beach’ those on in situ parent rock are subdivided on the basis (such as occurs at Rarangi, Marlborough) is defined as of rock chemistry. being a (1) raw to recent soil (2) of gravel to cobbles The diagnostic classifiers in our classification are (3) forming a beach (4) near the coast (raw–recent/ intentionally broad, and combine some of the finer gravel–cobbles/beach/coastal). Nearby, there may be distinctions in the biophysical categories of Myers et al. a ‘stony beach ridge’ defined as (1) raw to recent (2) of (1987) and Lawless et al. (1994, unpubl. draft report), gravel to cobbles (3) forming a beach ridge (4) near the for example. This was done both to simplify the list and coast (raw–recent/gravel–cobbles/beach ridge/coastal). to define the environments of the ecosystem types in In this example, only the landform differentiates these fairly general terms, as the sources of variation within two systems. ‘Coastal cliffs on basalt’, such as those many of them are poorly understood. More specifically on Banks Peninsula, are defined as being (1) raw soil defined diagnostic classifiers (e.g. of bedrock types and (2) of basic rock (3) forming cliffs (4) near the coast degree of foliation or bedding, climate and landform) (raw/basic/cliffs/coastal). They are distinguished from may eventually be required to describe how plant and ‘calcareous coastal cliffs’, such as those at Punakaiki, animal communities vary within these environments. North Westland, by the nature of their parent rock, i.e. defined and named as raw/limestone rock/cliffs/ Definitions and names of historically rare coastal. ecosystems A few environments are so extreme that only one The list of historically rare ecosystems (Table 2) was or two diagnostic classifiers are needed to separate derived from those listed in Rogers & Walker (2002), them as an ecosystem type, e.g. (1) geothermal (2) Rogers et al. (2005), the environments and ecosystems acid rain systems (geothermal–acid rain), or (1) seabird listed in Wardle (1991), de Lange et al. (2004), guano deposits (2) near the coast (seabirds–guano suggestions offered following presentations made at deposits/coastal (numerous landforms)). In Table 2 the 2005 meetings of the Plant Conservation Network information that is not part of the formal description and the New Zealand Ecological Society, and our own but is important to further characterise the ecosystem knowledge. A draft ordered list (with accompanying type is presented in parentheses. text) was reviewed by 48 individuals including experts Where diagnostic classifiers are held in common, from the Department of Conservation, regional councils, ecosystem types may be grouped together as is done universities and research institutes, private consultants, in Table 2. This is an intuitive clustering procedure and retired researchers (see Acknowledgements). This that serves to bring some order to the whole list. First, process doubled the number of systems on the list, all rare environments having unique hydrological refined the diagnostic classifiers used, and increased conditions and classified as wetlands by Johnson & the clarity of the rationale. A revised list was sent Gerbeaux (2004) are separated out and listed at the back to all the reviewers for a subsequent round of end of Table 2. Next, all those with either extreme comments. The list now includes 17 wetland types, chemical/physical or biological factors are grouped 3 types induced by native vertebrates, 5 subterranean and placed before wetlands. The biological group all types, and 5 geothermal types. The remainder include have high disturbance and added nutrients and although 11 exclusively coastal types and 30 types that may occur mainly coastal, some seabird colonies are found well in inland or alpine areas. Nevertheless, it should be inland. Those environments characterised by limited regarded as a first approximation and is undoubtedly an light or no light, such as caves and underground systems, incomplete list, especially with regard to environments are grouped as semi-subterranean or subterranean, of historically rare forested ecosystem types and those and geothermal environments are grouped together. restricted to alpine areas. The list errs on the side Groupings of the remaining environments (the majority) of including physical environments for ecosystem start at the top of the table. They are grouped first by types that subsequently may be determined not to be a coarse-scale climate classifier, or a range of climate historically rare (e.g. sand dunes), so as not to omit classifiers. Within each group so defined, they are then those whose original rarity is currently uncertain. listed according to whether they primarily have deposits For each defined environment, the main vegetation of parent material (e.g. sand dunes, talus, moraines) or structural units (adapted from Atkinson 1985) typical occur primarily on in situ parent rock (e.g. cliffs, scarps, of the rare ecosystem types are given (Table 2). tors). Last, environments within these groups are listed in order of increasing soil development, from raw to mature, and/or increasing particle size, from sand to boulders, or according to the chemical composition of WILLIAMS ET AL.: PHYSIOGNOMIC FRAMEWORK FOR RARE ECOSYSTEMS 125

Table 2. Physical environments and vegetation structure of New Zealand’s historically rare ecosystems. The common name and definition describe the environment of the ecosystem type. Vegetation structure lists the main vegetation units across all occurrences of that ecosystem and uses categories adapted from Atkinson (1985) – forest, treeland, scrub, shrubland, tussockland, fernland, grassland, sedgeland, rushland, reedland, restiadland, cushionfield, herbfield, mossfield, lichenfield, and open land (includes rockland, boulderfield, stonefield/gravelfield, sandfield, loamfield/peatfield). * indicates that rarity at a national scale may be questionable. Information that is not part of the formal description but is important to further characterise the ecosystem type is given in parentheses. ______Tentative common name Definition (i.e. diagnostic classifiers) Vegetation structure Example locality and notes ______Coastal *Active sand dunes raw/sand/dune/coastal grassland, sedgeland, open land Himatangi, Manawatu Dune deflation hollows raw/sand/depression/excessive open land Kaitorete Spit, Canterbury drainage/coastal Shell barrier beaches raw/shells/plain/coastal grassland, herbfield Miranda Chenier Plain, Firth of Thames Coastal turfs raw/atmospheric salinity/coastal, open land, herbfield Westhaven Inlet, NW extreme exposure Nelson Stony beach ridges raw–recent/gravel–cobbles/beach scrub, shrubland, open land Rarangi, Marlborough ridge/coastal Shingle beaches raw–recent/gravel–cobbles /beach/coastal open land Rarangi, Marlborough *Stable sand dunes recent/sand/dune/coastal shrubland, grassland, tussockland, Himatangi, Manawatu herbfield, open land Coastal rock stacks raw/acidic rock/tor/coastal open land, herbfield, lichenfield, Cape Kidnappers, Hawke’s Bay shrubland Coastal cliffs on raw/quartzose rock/cliffs/coastal open land, lichenfield, herbfield, 17 Mile Bluff, Westland quartzose rocks scrub, shrubland tussockland Coastal cliffs on acidic raw/acidic rock/cliffs/coastal open land, lichenfield, herbfield, Cape Turnagain, rocks scrub, shrubland tussockland Wairarapa Basic coastal cliffs raw/basic rock/cliffs/coastal open land, lichenfield, herbfield, Coastal areas of Banks scrub, shrubland tussockland Peninsula, Calcareous coastal cliffs raw/limestone rock/cliffs/coastal open land, lichenfield, herbfield, Punakaiki, North Westland scrub, shrubland tussockland Ultrabasic sea cliffs raw/ultrabasic rock/cliffs/coastal scrub, herbfield, lichenfield, open land Western cliffs, D’Urville Island; Surville cliffs, Northland Inland and alpine systems Volcanic dunes raw/acidic rock (volcanics)/sand/dune open land Rangipo Desert, central North Island *Screes of acidic rocks raw/acidic rock/gravel– open land Porters Pass, Canterbury cobbles/talus/(excessive drainage–near permanently saturated; inland–alpine) Calcareous screes raw/calcareous rock/gravel–cobbles open land Mt Arthur, Nelson /talus/(excessive drainage–near permanently saturated; inland–alpine) Ultrabasic screes raw/ultrabasic rock/gravel–cobbles/talus open land, lichenfield, shrubland Olivine Range, Southland /(excessive drainage–near permanently saturated) Young tephra (<500 years) raw/acidic rock(volcanic) /sand– open land Mt Tarawera, Rotorua plains and hillslopes gravel/plains and hillslope Recent lava flows raw/acidic rock (volcanic)/boulders– scrub, shrubland, treeland, forest, Rangitoto Island, Auckland (<1000 years) bedrock (numerous landforms) herbfield, mossfield, open land Old tephra (>500 years) acidic rock (volcanic)/depression/ shrubland, scrub, tussockland Kaingaroa, central North Island plains (= frost flats) seasonally fluctuating water table/inland, >200 frost days year Frost hollows terrace/>200 frost days per year shrubland, scrub Buller River, Nelson Boulderfields of acidic raw/acidic rock/boulders/talus open land, lichenfield, shrubland Iron Hill, western Nelson rocks (non-volcanic) Volcanic boulderfields recent/acidic(volcanic)/boulders/talus/ forest, scrub Mt Eden, Auckland excessive drainage Volcanic debris flows or recent/acidic rock(volcanic)/silt–cobbles forest, scrub, mossfield Maero debris flow, Mt Taranaki lahars *Moraines raw–recent/cobbles– open land, shrubland, herbfield, Murchison Valley, Canterbury boulders/moraine/(various parent materials) tussockland Boulderfields of calcareous raw/calcareous rock/boulders/talus open land, lichenfield, shrubland Mt Arthur, western Nelson rocks Ultrabasic boulderfields raw/ultrabasic rock/boulders/talus open land, lichenfield, shrubland Red Hills, Southland Cliffs, scarps and tors of raw/quartzose rock/bedrock/cliff, scarp open land, herbfield, tussockland, Lyell Range, Westland quartzose rocks and tor/inland–alpine shrubland *Cliffs, scarps and tors of raw/acidic rock/bedrock/cliff, scarp and open land, herbfield, tussockland, Mt Rolleston, Canterbury acidic rocks tor/inland–alpine shrubland Basic cliffs, scarps and tors raw/basic rock/cliff, scarp and tor/inland– open land, herbfield, tussockland, Mt Herbert, Banks Peninsula, alpine shrubland Canterbury Calcareous cliffs, scarps raw/calcareous rock/cliff, scarp and open land, herbfield, tussockland, Mt Owen, Nelson and tors tor/inland–alpine shrubland Ultrabasic cliffs, scarps raw/ultrabasic rock/cliff, scarp and open land, herbfield, tussockland, Olivine Range, Southland and tors tor/coastal–alpine shrubland ______126 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 31, NO. 2, 2007

______Tentative common name Definition (i.e. diagnostic classifiers) Vegetation structure Example locality and notes ______

Ultrabasic hills ultrabasic rock/hillslope, hillcrest/(raw– open land, herbfield scrub, shrubland, Red Hills, Marlborough mature) tussockland, forest (very limited extent) Inland sand dunes raw–recent/sand/dune/inland open land, scrub, tussockland, herbfield Clutha Valley, Otago Inland outwash gravels raw–recent/sand–boulders/plain/inland open land, herbfield, treeland Pisa Flats, Clutha Valley Braided riverbeds raw–recent/sand–boulders/plain/periodically open land, herbfield Waimakariri River flooded (2JG, p. 56) Granitic sand plains raw/granite/sand–gravel/hillslope, hillcrest open land Lookout Range, Nelson (mostly alpine) Granitic gravel fields raw/granite/gravel/hillslope, hillcrest open land Mt Titiroa, Manapouri Sandstone erosion raw/quartzose/bedrock/hillslope, hillcrest open land Mt Augustus, West Coast pavements Limestone erosion raw/calcareous/bedrock/hillslope, open land Matiri Tops, western Nelson pavements hillcrest/(alpine) Inland saline (salt pans) ground water salinity/semi herbfield, grassland Maniototo Valley, Central Otago arid/depression (2JG, p. 20, 22) Strongly leached terraces over-mature/sand–gravel/ open land, herbfield, shrubland The Wilderness, Southland and plains (‘Wilderness’ terrace–plain/inland vegetation) Cloud forests high cloud cover (<1500 sunshine hours forest Mt Manuoha, Urewera National and >200 rain days p.a.)/inland Park; Waima Forest, western Northland Geothermal systems Heated ground (dry) geothermal – excessive heat open land, mossfield, shrubland, scrub Whakarewarewa, Rotorua Hydrothermally altered geothermal – acid soils, toxic elements open land, shrubland, scrub Whakarewarewa, Rotorua ground (now cool) Acid rain systems geothermal – acid rain open land, scrub, treeland, forest White Island, Bay of Plenty Fumeroles geothermal – superheated steam/acid open land, shrubland Waimangu, Rotorua rain/depression Geothermal streamsides geothermal – excessive heat/near open land to scrub Waimangu, Rotorua permanently saturated (but water table not high) Induced by native vertebrates *Seabird guano deposits seabirds – guano open land, herbfield Muriwai gannet colony, deposits/coastal/(numerous landforms) Auckland; South Bay, Kaikoura *Seabird burrowed soils seabirds – burrowing/coastal open land to forest Petrel colonies, Paparoas; Catlins Coast, SE Otago Marine mammal haulouts seabirds and marine mammals – open land to forest Seal colonies, Westport trampling and grazing/coastal Subterranean or semi-subterranean Sinkholes raw/limestone, marble, dolomite/doline open land, shrubland, tussockland, Thousand Acre Plateau, western flaxland Nelson Cave entrances raw/calcareous/cave entrance open land, herbfield Mangapu cave Caves, and cracks in karst calcareous/subterranean/coastal–alpine none Waitomo caves, Waikato *Subterranean river gravels raw/alluvium and till/gravel/subterranean/ none Waimea Plains Subterranean basalt fields raw/basic rock (basalt)/subterranean none beneath Auckland city Wetlands Lake margins inland/regularly high water table/silt and open land, herbfield, rushland Lake Te Anau, Fiordland clay–gravel/beach (2JG, p. 18) Cushion bogs permanently high water table/peat/plain cushionfield Mararoa Valley, Southland (2JG, p. 27) Ephemeral wetlands1 seasonally high water table/depression herbfield, open land Rangitaiki, Taupo (2JG, p. 33) Gumlands (excludes those over-mature soils/seasonally high water shrubland, fernland, sedgeland, forest Ahipara Plateau; Spirits Bay, induced by anthropogenic table/(peat or non-peat) (2JG, p. 34) Northland fire) Pakihi over-mature soils/regularly–permanently shrubland, fernland, sedgeland, forest German Terrace, Westland high water table/(peat or non-peat) (2JG, p. 34) Damp sand plains raw–recent/coastal/sand/plains/permanently open land, herbfield Kaipara Heads, Northland high water table (2JG, p. 44) Dune slacks raw–recent/coastal/sand/depression/ herbfield, open land Himatangi, Manawatu permanently or seasonally high water table (2JG, p. 44) Domed bogs (Sporadanthus) permanently high water table/peat/dome restiadland, rushland, sedgeland, shrubland Kopuatai Bog, Hauraki Plains (2JG, pp. 48, 70) String mires permanently high water table/ mossfield, sedgeland Garvie Mountains, Southland peat/depression on hillslope/open water (2JG, p. 48) ______WILLIAMS ET AL.: PHYSIOGNOMIC FRAMEWORK FOR RARE ECOSYSTEMS 127

______Tentative common name Definition (i.e. diagnostic classifiers) Vegetation structure Example locality and notes ______

*Blanket mires permanently high water rushland, mossfield, fernland, shrubland, Southern Stewart Island table/peat/hillcrest, hillslopes, depressions scrub, forest (low relief) (2JG, p. 50) Tarns open water/depression/alpine tussockland, sedgeland, cushionfield Glenmore moraines, Mackenzie (usually) (2JG, p. 53) Basin *Estuaries coastal/estuary (2JG, p. 54) open land, sedgeland, rushland, Ohiwa Harbour, Bay of Plenty; reedland, herbfield, shrubland, scrub Whangapoua estuary, Great Barrier Island *Lagoons coastal/lagoon (2JG, pp. 54–55) open land, sedgeland, rushland, Lake Ellesmere, Canterbury reedland, herbfield, shrubland, scrub Seepages and flushes permanently high water table/hillslope sedgeland, cushionfield, mossfield, Garvie Mountains, Southland and fan/enhanced nutrients (2JG, pp. 57–58) scrub Snow banks alpine/late snow-lie/seasonally high water tussockland, herbfield Top of Kelly Range, Brunner table (2JG, p. 62) Range ______1 May be usefully split into ‘acidic’ vs ‘basic’ to account for the very rare turfs surrounding karst lakes (e.g. Lake Koraha, Taumata Totara Forest) 2 (JG) See Johnson & Gerbeaux (2004)

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